Normally I'd reject the idea of a Time Travel expansion out of hand, if it wasn't for the Timeless Isle and the Bronze Dragon traitor questline. It seems like an odd thing to include as part of the final raid patch if they don't plan to have the next expac involve time travel in some way.
I don't think all of the "leaked" details are true, though. I recall past expansion leaks coming with a lot of incorrect details along with true stuff.